Prevalence of undiagnosed glucose intolerance and type 2 diabetes in patients with moderate-to-severe obstructive sleep apnea syndrome.

Purpose: Overweight and obesity are major causal factors for obstructive sleep apnea syndrome (OSAS), providing insight into why one third of patients with OSAS suffer from diabetes mellitus and another third from glucose intolerance. However, a significant proportion of the general population remains undiagnosed for glucose metabolism disorders. The primary aim of this study was to establish the prevalence of known and newly diagnosed glucose metabolism disorders in patients with moderate and severe OSAS referred to the sleep lab for continuous positive airway pressure (CPAP) therapy.
Methods: We prospectively included consecutive patients with moderate or severe OSAS referred for CPAP therapy. A fasting blood sample was collected to determine glycosylated hemoglobin (HbA1c), glucose, and homeostatic model assessment (HOMA) index. Baseline demographic data and medication intake were recorded.
Results: Of 280 consecutive patients (70% men, mean ± SD body mass index 33 ± 7 kg/m ² , apnea-hypopnea index 49 ± 25), 22% exhibited diabetes and 44% glucose intolerance. Undiagnosed diabetes and glucose intolerance was found in 79 of 280 patients (28%). Insulin resistance was associated with OSAS severity in multivariate linear regression analysis (regression coefficient 2.40 [95% CI 0.07-4.72]; p = 0.04).
Conclusion: In this population of overweight and obese patients with moderate and severe OSAS, 66% of patients had diabetes or glucose intolerance and 28% were newly diagnosed. Diabetes and glucose intolerance were not related to OSAS severity, contrary to insulin resistance. These data suggest that there is value in systematic screening for glucose metabolism disorders in all patients with moderate and severe OSAS.